This invention relates generally to gas turbine engines, and more particularly relates to rotors and shrouds in such engines.
A gas turbine engine includes, in serial-flow communication, a compressor, a combustor, and a turbine. The turbine is mechanically coupled to the compressor, and the three components define a turbomachinery core. The core is operable in a known manner to generate a flow of hot, pressurized combustion gases to operate the engine as well as perform useful work such as providing propulsive thrust or mechanical work.
A gas turbine engine includes several rotors each of which includes a rotating disk carrying an array of airfoils referred to as blades. The blades of each rotor are surrounded by a ring-shroud. The ring-shroud is configured to define a flowpath for gases and is supported by a casing. Ring-shrouds can be made from metallic materials or from single-piece ceramic matrix composites. The dimensions of the ring-shrouds define the clearances between the blades and an inner surface of the ring-shroud.
The clearances are conventionally very small. As a result, thermal expansion and relative movement of the rotor relative to the ring-shroud can cause contact between blades and the inner surface of the ring-shroud. This can lead to undesirable wear or damage.
Therefore there is a need for an apparatus to maintain a minimum clearance between the blades and the inner surface of the ring-shroud.